Merge tag 'for-6.13/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mikulas Patocka:

 - dm-array fixes

 - dm-verity forward error correction fixes

 - remove the flag DM_TARGET_PASSES_INTEGRITY from dm-ebs

 - dm-thin RCU list fix

* tag 'for-6.13/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm thin: make get_first_thin use rcu-safe list first function
  dm-ebs: don't set the flag DM_TARGET_PASSES_INTEGRITY
  dm-verity FEC: Avoid copying RS parity bytes twice.
  dm-verity FEC: Fix RS FEC repair for roots unaligned to block size (take 2)
  dm array: fix cursor index when skipping across block boundaries
  dm array: fix unreleased btree blocks on closing a faulty array cursor
  dm array: fix releasing a faulty array block twice in dm_array_cursor_end

Author: torvalds

drivers/md/dm-ebs-target.c

@@ -442,7 +442,7 @@ static int ebs_iterate_devices(struct dm_target *ti,
 static struct target_type ebs_target = {
 	.name		 = "ebs",
 	.version	 = {1, 0, 1},
-	.features	 = DM_TARGET_PASSES_INTEGRITY,
+	.features	 = 0,
 	.module		 = THIS_MODULE,
 	.ctr		 = ebs_ctr,
 	.dtr		 = ebs_dtr,

drivers/md/dm-thin.c

@@ -2332,10 +2332,9 @@ static struct thin_c *get_first_thin(struct pool *pool)
 	struct thin_c *tc = NULL;
 
 	rcu_read_lock();
-	if (!list_empty(&pool->active_thins)) {
-		tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
+	tc = list_first_or_null_rcu(&pool->active_thins, struct thin_c, list);
+	if (tc)
 		thin_get(tc);
-	}
 	rcu_read_unlock();
 
 	return tc;

drivers/md/dm-verity-fec.c

@@ -39,36 +39,24 @@ static inline u64 fec_interleave(struct dm_verity *v, u64 offset)
 	return offset + mod * (v->fec->rounds << v->data_dev_block_bits);
 }
 
-/*
- * Decode an RS block using Reed-Solomon.
- */
-static int fec_decode_rs8(struct dm_verity *v, struct dm_verity_fec_io *fio,
-			  u8 *data, u8 *fec, int neras)
-{
-	int i;
-	uint16_t par[DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN];
-
-	for (i = 0; i < v->fec->roots; i++)
-		par[i] = fec[i];
-
-	return decode_rs8(fio->rs, data, par, v->fec->rsn, NULL, neras,
-			  fio->erasures, 0, NULL);
-}
-
 /*
  * Read error-correcting codes for the requested RS block. Returns a pointer
  * to the data block. Caller is responsible for releasing buf.
  */
 static u8 *fec_read_parity(struct dm_verity *v, u64 rsb, int index,
-			   unsigned int *offset, struct dm_buffer **buf,
-			   unsigned short ioprio)
+			   unsigned int *offset, unsigned int par_buf_offset,
+			   struct dm_buffer **buf, unsigned short ioprio)
 {
 	u64 position, block, rem;
 	u8 *res;
 
+	/* We have already part of parity bytes read, skip to the next block */
+	if (par_buf_offset)
+		index++;
+
 	position = (index + rsb) * v->fec->roots;
 	block = div64_u64_rem(position, v->fec->io_size, &rem);
-	*offset = (unsigned int)rem;
+	*offset = par_buf_offset ? 0 : (unsigned int)rem;
 
 	res = dm_bufio_read_with_ioprio(v->fec->bufio, block, buf, ioprio);
 	if (IS_ERR(res)) {
@@ -128,11 +116,13 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io,
 {
 	int r, corrected = 0, res;
 	struct dm_buffer *buf;
-	unsigned int n, i, offset;
+	unsigned int n, i, j, offset, par_buf_offset = 0;
+	uint16_t par_buf[DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN];
 	u8 *par, *block;
 	struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
 
-	par = fec_read_parity(v, rsb, block_offset, &offset, &buf, bio_prio(bio));
+	par = fec_read_parity(v, rsb, block_offset, &offset,
+			      par_buf_offset, &buf, bio_prio(bio));
 	if (IS_ERR(par))
 		return PTR_ERR(par);
 
@@ -142,7 +132,11 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io,
 	 */
 	fec_for_each_buffer_rs_block(fio, n, i) {
 		block = fec_buffer_rs_block(v, fio, n, i);
-		res = fec_decode_rs8(v, fio, block, &par[offset], neras);
+		for (j = 0; j < v->fec->roots - par_buf_offset; j++)
+			par_buf[par_buf_offset + j] = par[offset + j];
+		/* Decode an RS block using Reed-Solomon */
+		res = decode_rs8(fio->rs, block, par_buf, v->fec->rsn,
+				 NULL, neras, fio->erasures, 0, NULL);
 		if (res < 0) {
 			r = res;
 			goto error;
@@ -155,12 +149,22 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io,
 		if (block_offset >= 1 << v->data_dev_block_bits)
 			goto done;
 
-		/* read the next block when we run out of parity bytes */
-		offset += v->fec->roots;
+		/* Read the next block when we run out of parity bytes */
+		offset += (v->fec->roots - par_buf_offset);
+		/* Check if parity bytes are split between blocks */
+		if (offset < v->fec->io_size && (offset + v->fec->roots) > v->fec->io_size) {
+			par_buf_offset = v->fec->io_size - offset;
+			for (j = 0; j < par_buf_offset; j++)
+				par_buf[j] = par[offset + j];
+			offset += par_buf_offset;
+		} else
+			par_buf_offset = 0;
+
 		if (offset >= v->fec->io_size) {
 			dm_bufio_release(buf);
 
-			par = fec_read_parity(v, rsb, block_offset, &offset, &buf, bio_prio(bio));
+			par = fec_read_parity(v, rsb, block_offset, &offset,
+					      par_buf_offset, &buf, bio_prio(bio));
 			if (IS_ERR(par))
 				return PTR_ERR(par);
 		}
@@ -724,10 +728,7 @@ int verity_fec_ctr(struct dm_verity *v)
 		return -E2BIG;
 	}
 
-	if ((f->roots << SECTOR_SHIFT) & ((1 << v->data_dev_block_bits) - 1))
-		f->io_size = 1 << v->data_dev_block_bits;
-	else
-		f->io_size = v->fec->roots << SECTOR_SHIFT;
+	f->io_size = 1 << v->data_dev_block_bits;
 
 	f->bufio = dm_bufio_client_create(f->dev->bdev,
 					  f->io_size,

drivers/md/persistent-data/dm-array.c

@@ -917,23 +917,27 @@ static int load_ablock(struct dm_array_cursor *c)
 	if (c->block)
 		unlock_ablock(c->info, c->block);
 
-	c->block = NULL;
-	c->ab = NULL;
 	c->index = 0;
 
 	r = dm_btree_cursor_get_value(&c->cursor, &key, &value_le);
 	if (r) {
 		DMERR("dm_btree_cursor_get_value failed");
-		dm_btree_cursor_end(&c->cursor);
+		goto out;
 
 	} else {
 		r = get_ablock(c->info, le64_to_cpu(value_le), &c->block, &c->ab);
 		if (r) {
 			DMERR("get_ablock failed");
-			dm_btree_cursor_end(&c->cursor);
+			goto out;
 		}
 	}
 
+	return 0;
+
+out:
+	dm_btree_cursor_end(&c->cursor);
+	c->block = NULL;
+	c->ab = NULL;
 	return r;
 }
 
@@ -956,10 +960,10 @@ EXPORT_SYMBOL_GPL(dm_array_cursor_begin);
 
 void dm_array_cursor_end(struct dm_array_cursor *c)
 {
-	if (c->block) {
+	if (c->block)
 		unlock_ablock(c->info, c->block);
-		dm_btree_cursor_end(&c->cursor);
-	}
+
+	dm_btree_cursor_end(&c->cursor);
 }
 EXPORT_SYMBOL_GPL(dm_array_cursor_end);
 
@@ -999,6 +1003,7 @@ int dm_array_cursor_skip(struct dm_array_cursor *c, uint32_t count)
 		}
 
 		count -= remaining;
+		c->index += (remaining - 1);
 		r = dm_array_cursor_next(c);
 
 	} while (!r);